https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79706
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |rejects-valid
Status|UNCONFIRMED |NEW
Last reconfirmed| |2017-02-24
Ever confirmed|0 |1
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This means libstdc++ can't use SFINAE to check if a delete[] expression is
well-formed:
namespace std {
template<typename T> T&& declval();
template<typename, typename = void> struct result_of { };
template<typename F, typename A>
struct result_of<F(A), decltype(declval<F>()(declval<A>()))>
{
using type = decltype(declval<F>()(declval<A>()));
};
}
template<bool _Array, typename _Yp, typename = void>
struct can_delete { };
template<typename _Yp>
struct can_delete<true, _Yp, decltype(delete[] std::declval<_Yp*>())>
{ void operator()(_Yp*) const; };
template<typename _Yp>
struct can_delete<false, _Yp, decltype(delete std::declval<_Yp*>())>
{ void operator()(_Yp*) const; };
struct A {
void operator delete[](void*) = delete;
void operator delete(void*) = delete;
};
std::result_of<can_delete<true, A>(A*)> r;
The result_of primary template should be used, but instead we get errors (or
one error, five times) while trying to match the partial specialization:
sp.cc: In instantiation of ‘struct can_delete<true, A>’:
sp.cc:6:49: required by substitution of ‘template<class F, class A> struct
std::result_of<F(A), decltype (declval<F>()(declval<A>()))> [with F =
can_delete<true, A>; A = A*]’
sp.cc:28:41: required from here
sp.cc:17:3: error: use of deleted function ‘static void A::operator delete
[](void*)’
{ void operator()(_Yp*) const; };
^
sp.cc:24:8: note: declared here
void operator delete[](void*) = delete;
^~~~~~~~
sp.cc:17:3: error: use of deleted function ‘static void A::operator delete
[](void*)’
{ void operator()(_Yp*) const; };
^
sp.cc:24:8: note: declared here
void operator delete[](void*) = delete;
^~~~~~~~
sp.cc:17:10: error: use of deleted function ‘static void A::operator delete
[](void*)’
{ void operator()(_Yp*) const; };
^~~~~~~~
sp.cc:24:8: note: declared here
void operator delete[](void*) = delete;
^~~~~~~~
sp.cc:17:10: error: use of deleted function ‘static void A::operator delete
[](void*)’
{ void operator()(_Yp*) const; };
^~~~~~~~
sp.cc:24:8: note: declared here
void operator delete[](void*) = delete;
^~~~~~~~
sp.cc:17:27: error: use of deleted function ‘static void A::operator delete
[](void*)’
{ void operator()(_Yp*) const; };
^~~~~
sp.cc:24:8: note: declared here
void operator delete[](void*) = delete;
^~~~~~~~
